>> at that point we were pretty certain that there were some hackers in our network, and the fbi said, as did at&t, that this had all the hallmarks of hacking by the chinese military. >> reporter: officials at the department of homeland security pulled up some numbers to illustrate what's happening. they say hackers just hit nine u.s. firms in 2009. two years later, that figure jumped to 198. analysts at a computer consumer firm blame a unit of the chinese military. the analysts issued this report exposing chinese espionage units, and they referred to hackers as the advanced persistent threat. they said the groups conducting these activities are based primarily in china, and they say the chinese government is aware of them. the analysts say a group known as apt1 has targeted nearly 150 victims over seven years, institutions and companies around the world. they concluded that the group is likely government sponsored. they traced apt1 to four computer networks in shanghai.